Drilling tool



Nov. 22, 1938.

Filed Oct. 9, 1937 w M MW h R W m M. W Em...

WW1 WW 4 2 2 0 6 a 0 5 w ll 1 d 3 9a 2 94 3 3 9 2 a 1 m \w F Patented Nov. 22, 1938 UNITED STATES DRILLING TOOL Edward F. Terry, Phillipsburg, N. J., assignor to Ingersoll-Band Company, Jersey ,City,IN. J., a corporation of New Jersey Application October 9, 1937, Serial No. 168,193

1 Claim.

This invention relates to drilling tools, and more particularly to drilling tools of which the cutting bit is formed as a separate member and attachable to the shank serving to transmit the 5 glows of the percussive element to the cutting One object of the invention is to assure an ample supply of cleansing fluid directly to the source of cuttings.

Another object is to assure the utilization of the full force of pressure of the cleansing fluid for dislodgingand removing cuttings from the bottom of the hole being drilled.

A further object is to simplify and cheapen'the construction of devices of this character.

, Other objects will be in part obvious and in part pointed out hereinafter. s

In the drawing accompanying this specification,

Figure 1 is an end view of a -cutting tool constructed in accordance with the practice of 'the invention, and

Figure 2 is an elevation, the drilling tool.

Referring more particularly to the drawing, designates a drill bit and 2| a shank through which the blows of a percussive element, such as a rock drill of the hammer type (not shown), are transmitted to the cutting bit for actuating it.

In the,form of the invention illustrated the cutting bit comprises a body portion or skirt 22 carrying a plurality of cutting wings 23 at'its front end. Any suitable number of cutting wings 23, may be provided, four being shown in the present instance and arranged in cruciform fashion. Each cutting wing is provided with the usual crushing surfaces 24 which converge to define radial cutting edges 25. The cutting wings 23 extend beyond the periphery of the skirt 22, and theportions thus projecting are reenforced by'buttresses 26 extending longitudinally of the skirt 22.

In accordance with the practice of the invention, the skirt 22 is provided with a bore 21 extending from end to end of the skirt to accommodate a stem 28 carried by the shank 2|. The stem 28 extends entirely through the bore 21 and its front surface 29 is of convex shape and coin-- cides with partly circular surfaces 30 on the skirt 22 and forming the bottoms of grooves 3| which define the side surfaces of the portions of the cutting wings lying in the plane of the skirt and serve as outlets for the cuttings and the cleansing agent conveying the cuttings from the bottom of the hole being drilled. v

Preferably, the bore 21 consists or an enlarged partly in section, of

portion 32 and a reduced portion 33 of which the former serves as a bearing for a pilot 34 on the stem 28 adjacent the juncture of the stem and the shank 2!. The front end of the reduced portion 33 serves a similar function for a pilot 35 on 5 the forward extremity of the stem 28, and intermediate the pilots 34 and.35 are threads 36 to cooperate with threads 31 in the reduced portion 33 of the bore 21 for securing the drill bit to, the shank 2i.

As a preferred form of construction, the rearward end of the skirt 22 constitutes a seating surface 38 for a shoulder 39 on the shank 2| adjacent the stem 28 to provide a wide path through which the force of the blows may travel to the 15 skirt 22 and thus to the cutting wings 23.

The shank 2| is hollow, having a passage 40 for conveying cleansing fluid, as for example water or compressed air, or both, to a hole being drilled. The passage III also extends through the stem 28 '20 so that the cleansing fluid is projected directly against the point at which the cuttings are formed and without passing through channels other than that defined by the shank.

In practice the present invention has been found to possess certain advantages that are highly desirable in devices of this character.- By extending the stem 28 entirely through the drill bit, rather than form a water passage in the drill bit, the same volume of cleansing fluid and 30 under the same pressure may be supplied to the work irrespective of whether a tight or loose joint exists between the drill bit and the shank. As a consequence an uninterrupted stream of undiminished force may be constantly directed 35 against the work, thus eliminating the chances of the cuttings plugging up the outlet opening of the passage. Moreover, by utilizing the portions of the stem lying forwardly and rearwardly of the threads as pilots the bit will be restrained 40 from tilting with respect to the stem in the event that the bit becomes partly unthreaded and in that way the threads will be protected against damage due to friction between the bit and the shank.

I claim:

A drilling tool, comprising a hollow body portion, cutting wings on the body portion, a shank extending through the body portion, interlocking threads on the shank and the body portion, pilot 5 portions on the shank forwardly and rearwardly of the threads to engage the body portion, convex surfaces between the cutting wings, and a convex surface on the shank coinciding with the said convex surfaces. 66

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